Manuel del Río was a Spanish Franciscan, said to have been a skilled watchmaker, who probably learned the trade in Oporto, Portugal, with Tomás Luis de Sáa. Del Río belonged to the Franciscan community in Santiago, where in 1759 he published Arte de los reloxes de ruedas (The art of making mechanical timepieces). The work was reissued in 1789 in Madrid by del Río’s disciple Ramón Durán. That edition is presented here. The prologue states that one of the reasons for writing the book was the lack of manuals ...